1. Field of the Invention
The present invention relates to the preparation of dialkoxybutenes, and, more especially, to the selective preparation of dialkoxybutenes by reacting 1,3-butadiene with an alcohol in the presence of oxygen and particular composite catalyst.
GB-A-1,138,366 describes the preparation of 1,4-dimethoxy-2-butene by reacting 1,3-butadiene with methanol in the presence of a solution of palladous chloride and cupric chloride dihydrate. It also suggests that reactions of this type be conducted in liquid phase in the presence of salts other than nitrates and sulfates or of coordination compounds of palladium, platinum, nickel, iron or cobalt and of an inorganic redox system. However, the efficiency of this process remains low in homogeneous phase; the yield of dimethoxybutenes is insufficient and a significant amount of byproducts is obtained.
2. Description of the Prior Art
U.S. Pat. No. 4,533,761 describes the preparation of dialkoxybutenes by reacting 1,3-butadiene with an alkanol, the alkanol constituting the reaction medium, in the presence of iodide and copper ions.
However, this reaction appears to be stoichiometric relative to the copper and the undesired formation of various byproducts is again observed.